§47-12-405. Tires and wheels — Peripheral equipment — Unsafe operating condition.
A. Every solid rubber tire on a vehicle shall have rubber on its entire traction surface at least one inch thick above the edge of the flange of the entire periphery.
B. A person shall not operate or move on any hard-surfaced highway any vehicle having any metal tire in contact with the roadway, except when authorized by special permit as provided in subsection E of this section.
C. 1. Any tire on a vehicle moved on a highway shall not have on its periphery any block, stud, flange, cleat or spike or any other protuberance of any material other than rubber which projects beyond the tread of the traction surface of the tire, except that it shall be permissible:
- to use farm tractors or implements of husbandry with tires having protuberances which will not injure the highway,
- to use tire chains of reasonable proportions upon any vehicle when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid, or
- for pneumatic tires equipped with or having on their periphery studs of metal, porcelain or other material to be sold or used in this state, if constructed to provide resiliency upon contact with the road surface, so that not more than three percent (3%) in the aggregate of the traction surface of such tire be composed of such studs and so that such studs do not project more than three thirty-seconds (3/32) of an inch beyond the tread of the traction surface of such tire and have a rate of wear which will so limit such projection.
2. The exceptions permitted in paragraph 1 of this subsection shall be subject to the following restrictions:
- the use of such tires or tire chains shall be limited to vehicles with rated capacities up to and including two (2) tons,
- any tire so equipped shall not be used on a public highway earlier than November 1 of each year or later than April 1 of the following year, and
- copies of this subsection shall be posted in all places at which tires or tire chains are sold, and a printed or written warning on the time limitation for the use of such tires or tire chains shall be furnished to each buyer, purchaser, or user by the seller of such studded tires or tire chains.
D. Operator selectable “on demand” studded tires having traction-enhancing studs located outside the normal tread area which allows their operation as conventional tires on dry roads or as studded tires on ice-coated roads by the expedient of reducing or increasing the air pressure within the tires, shall be exempt from the prohibitions of subsection C of this section with the following exceptions:
- The use of such tires shall be limited to vehicles with rated capacities up to and including two (2) tons;
- Any such tire shall not be deflated so that the studs lower and make contact with the road surface earlier than November 1 of each year or later than April 1 of the following year.
E. The Department of Public Safety and local authorities in their respective jurisdictions may in their discretion issue special permits authorizing the operation upon a highway of traction engines or tractors having movable tracks with transverse corrugations upon the periphery of such movable tracks or farm tractors or other farm machinery, the operation of which upon a highway would otherwise be prohibited under this section.
F. A person shall not operate any vehicle when one or more of the tires in use on that vehicle is in unsafe operating condition or has a tread depth less than two-thirty-seconds (2/32) inch measured in any two adjacent tread grooves at three equally spaced intervals around the circumference of the tire; provided, such measurements shall not be made at the location of any tread wear indicator, tie bar, hump, or fillet. As used in this subsection, an unsafe tire includes, but is not limited to, any tire:
- On which the ply or cord is exposed in the tread area;
- Which has been regrooved or recut below the original groove depth, except tires that have been designed with under-rubber sufficient for regrooving and are so marked;
- Marked “Farm Implement Only”, “Not for Highway Use”, or any other marking that would indicate that the tire is not for normal highway use; provided, no such marking shall be altered or removed;
- On which any bulges, bumps, or knots show in the tread or sidewall area; or
- On the front steering axle of a truck-tractor which has tread depth measuring less than four-thirty-seconds (4/32) inch.
G. Every wheel on a vehicle shall not be cracked and shall be securely fastened to the hub of the vehicle with all lug nuts properly affixed.